Table 1.

Information and preparation protocols of negative control samples.

NC Samples	Preparation Method	Specificity Evaluation
Without Scutellariae radix	①	baicalein and wogonin
Without Moutan cortex	②	paeonol
Without Polygoni cuspidate rhizome et radix	③	emodin

① All medicinal materials in Hu–gan–kang–yuan capsule, except for Scutellariae radix, were exactly weighed and exacted according to the Section 2.4.1. The extract solution was used as negative control sample to evaluate specificity for determining baicalein and wogonin; ② All medicinal materials in Hu–gan–kang–yuan capsule, except for Moutan cortex, were exactly weighed and exacted according to the Section 2.4.2. The extract solution was used as negative control sample to evaluate specificity for determining paeonol; ③ All medicinal materials in Hu–gan–kang–yuan capsule, except for Polygoni cuspidate rhizome et radix, were exactly weighed and exacted according to the Section 2.4.3. The extract solution was used as negative control sample to evaluate specificity for determining emodin.